2. VERTIBROBASILAR INSUFFICIENCY
Vertebrobasilar Insufficiency (VBI) is a posterior circulation transient ischemic attack
(TIA) caused by intermittent vertebral artery occlusion that is induced by a head rotation
or extension.
VBI also may result from large vessel atherosclerotic disease, dissection, cervical
compressive lesions, and subclavian steal phenomenon.
3. PATHOPHYSIOLOGY
Usually, VBI is caused by 2 processes of ischemia:
Hemodynamic insufficiency
Embolism.
Unlike the carotid arteries, embolism via the vertebral arteries is not common.
Donor sites for embolism may include the aortic arch, the origin of the vertebral artery
or the proximal subclavian arteries.
Most cases, however, are due to atherosclerotic disease.
4. HEMODYNAMIC
Decreased perfusion causes most VBI.
Hemodynamic ischemia occurs due to inadequate blood flow through the basilar
artery, especially in the elderly and diabetic populations with poor sympathetic control.
Symptoms tend to be reproducible and short, rarely causing infarction.
For hemodynamic ischemia to occur, there must be occlusion in both vertebral arteries
or within the basilar artery.
Also, there must be an incomplete contribution by the carotid circulation via the
posterior communicating artery in the circle of Willis.
5. Cont…
Other causes for a decrease in perfusion include antihypertensive medications, cardiac
arrhythmia, pacemaker malfunction, and vasculitis.
Thus, it is imperative that a complete workup, including ECG, be done to rule out
cardiogenic causes.
Occlusions in other blood vessels such as in Subclavian Steal syndrome may also
cause VBI by “stealing” blood flow from the brainstem as blood flows down the path of
least resistance via the vertebral artery in the presence of proximal stenosis/occlusion of
the subclavian artery.
6. EMBOLISM
VBI may also originate from atherosclerotic plaques that later break off to form
emboli.
However, emboli may also develop as a result of intimal defects secondary to trauma,
compression, and in a minority of cases from fibromuscular dysplasia, aneurysm or
dissection.
Possibly up to one-third of cases occur intracranially, as distal emboli form from
lesions within the subclavian, vertebral, or basilar artery.
Most lesions that form extracranially arise from an atherosclerotic build-up in one of
the vertebral arteries, and rarely the innominate or subclavian. In a very small number of
cases, thrombi can arise from an ectatic (distension) or fusiform basilar artery aneurysm
which may then embolize to more distal branches.
7. SIGNS AND SYMPTOMS
• Loss of vision in part or all of both eyes
• Double vision
• Numbness or tingling
• Vertigo (Spinning Sensation)
• Nausea and vomiting
• Slurred speech
• Loss of coordination, dizziness or
confusion
• Trouble swallowing
• Drop attack – Patient feels suddenly weak in
the knees and fall
• Paraesthesia
• Ataxia
8. RISK FACTORS
• Smoking
• Hypertension
• Hyperlipidemia
• Older age
• Gender: men have a higher risk before age 75; women have a high risk after 75.
• Family history
• Genetic factors
9. INVESTIGATIONS
• MRI/ MRA
• Duplex
• CT/ CTA
• Digital Subtraction Cerebral Angiography (DSA) is considered the “gold standard”
diagnostic test
Mild sedative is used
ECG is attached
Catheter placed starting in the groin
Contrast Material
DSA uses a computer to “subtract” or take out the bones and tissues in the area
viewed, so that only the blood vessels filled with the contrast dye are seen
12. REFERENCES
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Publishing; 2022 Jan-.
2. Lima Neto AC, Bittar R, Gattas GS, Bor-Seng-Shu E, Oliveira ML, Monsanto RDC, Bittar LF. Pathophysiology and
Diagnosis of Vertebrobasilar Insufficiency: A Review of the Literature. Int Arch Otorhinolaryngol. 2017 Jul;21(3):302-307.
3. Najafi MR, Toghianifar N, Abdar Esfahani M, Najafi MA, Mollakouchakian MJ. Dolichoectasia in vertebrobasilar arteries
presented as transient ischemic attacks: A case report. ARYA Atheroscler. 2016 Jan;12(1):55-8
4. Yuh SJ, Alkherayf F, Lesiuk H. Dolichoectasia of the vertebral basilar and internal carotid arteries: A case report and literature
review. Surg Neurol Int. 2013;4:153.
5. Lou M, Caplan LR. Vertebrobasilar dilatative arteriopathy (dolichoectasia). Ann N Y Acad Sci. 2010 Jan;1184:121-33.
6. Caplan LR. Atherosclerotic Vertebral Artery Disease in the Neck. Curr Treat Options Cardiovasc Med. 2003 Jul;5(3):251-
256.